Hidden Palace Zone

For the Hidden Palace Zone in Sonic & Knuckles, see Hidden Palace Zone (SK).

Hidden Palace Zone as seen in Sonic 2 Beta.

Hidden Palace Zone is the most famous of the "lost levels" from Sonic the Hedgehog 2 Beta, mainly because it remains in a corrupted form on the final version of the cart. It is an underground level with water, featuring sparkling gems. Many parts of the level were once grounds for debate, such as the "master emerald", but most theories have been generally accepted as false. Some hacks, like Sonic 2 Delta, have restored the level using the graphics from the beta version and level map and object data from the graphicless version in the final release.

Hidden Palace Zone contains a glowing bridge that is actually the same object as the bridge in Emerald Hill Zone but it checks the level number to make it glow. The idea of a bridge that will glow when Sonic runs on it was reused in Sonic 3's Icecap Zone.

An interview with Yuji Naka later revealed that Hidden Palace Zone was originally intended to be a single act sub-level where the player will be warped to after collecting the 7 Chaos Emeralds. Once there, they would recieve the power to morph into Super Sonic. The idea was ultimately killed and the ability was given to the player immediately.

In the Final Release of Sonic the Hedgehog 2

Hidden Palace is also playable in the final Sonic 2 if you have a Game Genie. You lock Sonic 2 onto it, start up the system, then type in this code: ACLA-ATD4 and enter the Level Select code when done (19, 65, 09, 17 in that order on Sound Test in Options). Then, go to the Level Select screen (A+Start at Main Menu while cursor is at "1 Player"), and select the Death Egg Zone. The level mainly is a green glitch with water at the bottom, and below the water is a bottomless pit. This level has no end, so the only way to get to Act 2 is that you use the capsule in the Debug Mode (1, 9, 9, 2, 1, 1, 2, 4 in that order at the Level Select Screen Sound Test and hold A+Start on the highlighted level) and jump on it. When you get through both acts, you will come out at the Death Egg Zone.